WO2011153674A1 - Deposition box for silicon-based thin film solar cell - Google Patents

Abstract

A movable deposition box (02) for silicon-based thin film solar cell comprises an electrode array composed of at least a group of cathode plates (203) and a piece of anode plate (208) which are set in a movable chamber, wherein a feeding socket (203-1) is positioned on a circular or semicircular concave surface in the center area on the backside of the cathode plates (203), a circular or semicircular end face (201-1) of a feeding component (201) which has a flat middle part contacts the signal feeding socket (203-1) and feeds in RF/VHF power signal, the anode plate (208) is grounded, and a shield cover (204) of the cathode plate has a through-hole (204-1) and is insulated from the cathode plate (203).

Description

 Deposition box of silicon-based thin film solar cell

 The invention discloses a solar cell technology, specifically a VHF power supply

(27. 12MHz~100MHz) Deposition box for driven silicon-based thin film solar cells.

Background technique

 At present, silicon-based thin film solar cells use plasma enhanced chemical vapor deposition (PECVD) to obtain single-junction or multi-junction photoelectric conversion P-I-N layers, which are commonly used in the thin film solar cell manufacturing industry. Plasma electrodeposition is performed in the reaction chamber by an electrode plate array composed of electrode plate assemblies. The RF capacitor-coupled parallel plate electrode reaction chamber is widely used for large-area deposition of thin films of amorphous silicon, amorphous silicon germanium, silicon carbide, silicon nitride, and silicon oxide. Electrodes with a support frame are often referred to in the industry as "clamps", and devices for mounting the device in a chamber for plasma chemical vapor deposition are also referred to as "deposition cassettes". Silicon-based thin-film solar cells are an important branch of the solar industry, and the parallel electrode plate capacitive discharge mode is one of the core technologies in the solar cell industry. 13. 56MHz RF is widely used in high-speed preparation of amorphous silicon-based thin film materials, with high production efficiency and low process cost. As the solar market demands for silicon-based thin film technology continues to increase, microcrystalline and nanocrystalline silicon-based thin film materials are highly regarded by the industry. However, in the microcrystalline process environment, the 13.56MHz RF wave-derived plasma has a small plasma concentration, a low deposition rate, a long time for depositing a film of sufficient thickness, and a large background contamination, resulting in a high impurity content of the film and poor photoelectric properties. , seriously affecting product quality and performance. How high-speed deposition becomes the key to successful service of crystalline silicon-based thin film technology.

VHF refers to a legal RF that has twice or more times the frequency of 13.56 MHz. In the industry, the application of more VHF is generally in the range of 27.12~200MHz. However, in the capacitive discharge mode, the standing wave effect and the skin effect caused by the very high frequency are very obvious, and increase as the driving frequency increases. Professor MA Lieberman of the University of California, Berkeley, conducted an in-depth study of these two effects. The results show that the critical condition of the VHF PECVD deposition film is that the free-space wavelength of the excitation frequency („) is much larger than the size factor (X) of the capacitive discharge electrode plate, and the skin depth (δ) is much larger than the thickness. Factor ( _η . ) Taking the discharge area lm ² as an example, at the excitation frequency of 60 MHz, λ X , δ ^ τ. Therefore, at this excitation frequency, the skin and standing wave effects are very obvious, resulting in the electrode on the lm ² electrode plate. It is not uniform. Therefore, how to realize uniform large-area discharge driven by VHF is one of the technical problems to be solved in the crystallization of silicon-based thin film technology, which has aroused great interest in the industry. In 2003, US Patent 2003/0150562A1 discloses a flat plate. In the capacitive coupling discharge, the magnetic field is used to improve the electric field non-uniformity caused by the very high frequency. Chinese Patent 200710150227. 4, 200710150228. 9, 200710150229. 3, discloses three designs of VHF electrodes, which are different by VHF signals. Feeding the form to obtain a uniform electric field. However, the existing problems are: 1) The electrode design structure of the VHF-PECVD reaction chamber is complicated; 2) The reason for continuing improvement is in production. Constantly cleaning and loading the reaction chamber and the electrode will cause deformation of the deformed electrode; 3) The contact area of the multi-point feed structure in the prior patent is small, and the path of each feed point is required to be symmetrical, and the connection conductor between the feed points There must be no contact with the cathode plate. Accurately, the connection conductor needs to be shielded from the cathode plate to achieve effective discharge. The practical requirements of these structural designs are harsh, and the factors determining the uniformity of discharge are too many, and cannot meet the requirements in production. Therefore, in industrial equipment, single-point feeding is the mainstream structure design, but due to the standing wave and skin effect, the single-point feeding structure can not meet the requirements of feeding high-frequency frequency boost. Existing deposition fixtures and electrodes have been further developed and improved in terms of practicality, and in the face of current market demands, quality is improved and costs are reduced. At the same time, a CVD deposition box system for processing or depositing multiple sheets of glass is also a development trend. For industrial products that can meet the high-volume production and adopt the effective VHF feed mode And design has important practical significance to the industry.

Summary of the invention The object of the present invention is to solve the problem of discharge non-uniformity driven by a very high frequency power supply, and to provide an electrode array composed of a completely conceptually designed electrode plate assembly for a large area VHF-PECVD deposition chamber capable of obtaining a uniform electric field. A multi-chip array of large-area VHF-PECVD electrode plates suitable for industrialization.

 The present invention provides a technical solution for depositing a cartridge for achieving the above tasks: including an electrode plate assembly, a signal feeding assembly and a chamber, further comprising a cathode plate shield, the chamber being a movable cavity with a roller a chamber in which an electrode array consisting of electrode plates is mounted, the feed inlet being located in a concave circular or semi-circular surface in the central region of the back surface of the cathode plate of the electrode plate, in its circular or semi-circular feed inlet The inner surface contact connecting signal feeding component is connected to the negative pole of the RF/VHF power supply signal, and is connected to the semicircular or circular end surface of the feeding signal component by surface contact, and the shielding plate of the cathode plate is provided with a through hole, the cathode plate and the cathode plate Insulating between the shields, the electrode array is at least one set of cathode plates and one anode plate;

 Solution A set of cathode plates and an anode plate of the deposition box refers to an effective discharge working surface of a cathode plate which is symmetrically placed by two faces of the anode plate. The cathode plate is a single-sided discharge, and the shield of the cathode plate comprises a ceramic insulating layer and a shielding layer, and the shielding cover covers the entire back surface and the side surface of the cathode plate.

 The electrode comprises a plurality of sets of cathode plates with a shield cover and a plurality of sets of grounded anode plates to form an electrode array with a certain interval of discharge.

 The shield also includes a shield for the RF/VHF power supply signal fed into the center of the back of the cathode plate and the sides. The signal feed assembly includes a copper feed core and an insulating layer and an outer shield.

 The signal feeding component is composed of a waist and a head, has a z-shape, a high temperature resistant ceramic edge layer at the waist, and a metal feeding core is an electric conductor composed of an RF/VHF feed line, and the other end of the electric conductor Cathode output and power supply matcher for RF/VHF power supply signals.

The solution of the present invention resides in a method, a signal feeding mode composed of an electrode plate assembly, a feeding assembly and a chamber, characterized in that an electrode array composed of an electrode plate is mounted in a movable roller chamber, and at least one set of electrode arrays a cathode plate and an anode plate, the feed inlet is located at the center of the back surface of the cathode plate of the electrode plate In the concave circular or semi-circular plane in the area, the surface of the circular or semi-circular surface is contacted and connected to the feeding component; the signal of the electrode plate is fed by the surface feeding method, and the one end of the component is fed into the semicircle The circular contact or the semi-circular surface feed inlet connected to the cathode plate contacts the RF/VHF power supply signal.

 The solution feeds the RF/VHF power supply signal into the electrode plate feed inlet by a plurality of sets of feed components and electrode plate assemblies in a surface feeding manner to form an electrode array having a certain discharge pitch.

 The feed assembly is a zigzag metal strip with a high temperature resistant ceramic insulation at the waist, and the metal feed core is an RF/VHF feed line forming an electrical conductor.

 The other end of the conductor that feeds the component is connected to the cathode output port and the power supply matcher including the RF/VHF power supply signal.

 The positive beneficial effect produced by the deposition box of the invention is different from the side feeding mode of the slot type cathode plate, and stable discharge with higher uniformity and larger discharge area can be obtained in the deposition box, the access capacitance is small, and the actual discharge power is obtained. Large, RF interference between the electrode plate arrays is small. It is also different from the central point feed of the cathode plate of the single-chamber deposition system. It has small access capacitance, small standing wave and skin effect, and integrated array type multi-chamber deposition, which greatly improves production efficiency. Therefore, by optimizing the VHF power supply feed form and the structure of the electrode plate, the RF/VHF large-area discharge uniformity problem is solved, which is also the premise of the high-speed and high-efficiency preparation technology of the crystallized silicon-based film. The present invention is applicable to large-area uniform discharge of very high frequency power supplies of any legal frequency of any power, 27. 12 MHz to 200 MHz. This structure can be applied to a multi-piece deposition system, greatly increasing productivity and reducing battery cost. The invention breaks through the limitations of the conventional electrode design technology, effectively eliminates the standing wave and skin effect caused by very high frequency, and achieves the industrial application level suitable for uniform discharge.

Figure 1. is a cross-sectional view of the deposition cartridge of the present invention.

Figure 2 is a schematic view of a deposition chamber of the present invention.

FIG. 3 is a schematic structural diagram of the signal feeding component 201 in FIG.

Figure 4 is a schematic view showing the structure of the cathode plate 203 of Figure 1 of the present invention. FIG. 5 is a schematic structural view of the cathode shield cover 204 of FIG.

Figure 6 is a schematic view showing the structure of Embodiment 1 of the present invention.

Figure 7 is a schematic view showing the structure of Embodiment 2 of the present invention.

Figure 8 is a schematic view showing the structure of Embodiment 3 of the present invention.

 In Figure 1-8, the deposition box 02 is fed by a signal feed assembly 201, an insulating shield 202, a cathode plate 203, a cathode plate shield 204, a substrate 206, an insulating strip 207, an anode plate 208, a grounded metal channel 209, and a lower The rear door panel 211, the upper rear door panel 212, the gas chamber 214, the front door panel 215, the side frame 216, the wheel 218, the gas duct 220, the lower bottom plate 221, and the like are formed by vapor deposition deposition in the vacuum chamber 01. The vacuum chamber 01 has a gas system inlet 101, a power system inlet 102, a vacuum chamber movable door 103, a track 104, and a vacuum system inlet 105.

 The deposition cassette of the present invention achieves the inventive task set forth above in a face-fed manner. Overcoming many problems that the existing multi-point feeding is difficult to overcome by the VHF-PECVD deposition technology of the crystallized silicon-based film, such as the complex electrode structure of the reaction chamber; the electrode is easy to deform and the contact area is small; the path distance between each feeding point Requires complete symmetry and complete shielding. However, the surface feed deposition deposition box design of the present invention does not have these problems, and can obtain problems such as uniform electric field and large-area chamber discharge, and particularly efficient use of the double-working surface of the anode plate, and at the same time, a CVD deposition box system for processing or depositing multiple sheets of glass. With the effective VHF surface feed mode, the industrial production process can be achieved, which can meet the needs of mass production of silicon-based thin film solar cells.

The present invention also contributes to substantially solving the problem of uniformity and uniformity of a high-speed deposited film layer driven by a very high frequency power source. The deposition cartridge 02 is placed in a vacuum chamber 01, which includes an electrode plate, a signal feed assembly, a chamber, and a cathode plate shield 204. The cathode plate 203 and the anode plate 208 of the parallel electrode plate, the feed inlet 203-1 is circular, the signal feeding assembly 201 is stepped including a waist portion and an end surface 201-1 is semicircular with the feed inlet 203-1 located at the shield The concave portion of the cathode plate 203 of the cover 204 corresponds to a concave circular surface, the waist is flat and easy to install, and the signal feeding loss is small, and the other head is 201-3 connected to the RF / The VHF power supply negative pole and the power supply matcher (not shown) are stepped, and a feed inlet having a semicircular end surface in contact with the electrode plate is formed in the deposition box of the grounding device. With insulation shielding protection (not shown).

detailed description

Example 1

 The electrode plate is vertical, the cathode plate feed inlet is circular, the signal feeding assembly is flat at the waist, and the feed surface is semi-circular.

The working principle of this embodiment will be described with reference to Figs. In the deposition cartridge 02, the two cathode plates 203 share one anode plate 208. The vapor deposition system is mainly composed of a vapor deposition chamber, a gas system, a power system, a vacuum system, a heating system, a control system, etc., and the gas system is mainly provided with various required gas and gas pipelines for vapor deposition, and the power supply system mainly provides The high-frequency or high-frequency power source that needs to be ionized into a plasma state during deposition. The vacuum system mainly provides equipment and pipelines for vacuum extraction during deposition. The heating system mainly heats the vapor deposition chamber, and the control system is mainly The deposition process and parameters are controlled, and the vapor deposition chamber is a device that deposits a gas on the substrate 206 and completes the coating. The gas deposition chamber is mainly grounded by a vacuum chamber 01 and a deposition box 02 with a scroll wheel 218. The vacuum chamber 01 is used to achieve a vacuum state, and the deposition cartridge 02 is used to effect plasma discharge, and a P-IN film layer is deposited on the substrate 206. The deposition box 02 includes a cathode plate 203, a cathode plate shield 204, an insulating strip 207, an anode plate 208, a signal feeding assembly 201, a shielding layer 202, a bottom plate 221, a gas chamber 214, a grounding metal channel 209, a front door plate 215, The upper rear door panel 212, the lower rear door panel 211, the side frame 216, and the wheel 218 are formed. The side frame 216 is welded into a quadrangular frame by a stainless steel square. The rectangular lugs 216 - 4 are fixed on the frame, and the gas chamber 214 and the lower bottom plate 221 are connected to the upper and lower sides of the side frame 216 to form a whole, in the gas chamber 214 and the lower bottom plate 221 A grounding metal channel 209 is connected to the opposite surface for fixing the anode plate 208 and the cathode plate 203, and the cathode plate shield 204. The anode plate 208 is directly inserted into the metal channel 209. The cathode plate shield 204 is in contact with the metal guide groove 209, and the insulating strip 207 is attached between the cathode plate 203 and the cathode plate shield 204 so as to be in contact with the groove. The anode plate 208 and the cathode plate shield 204 are grounded by contact with the metal guide groove 209 and then with the lower base plate 221. In the central portion of the back of the cathode plate 203, there is a concave circular feed inlet 203-1. The waist and the head of the signal feeding assembly 201 are formed in a zigzag shape, and the semicircular end face of the head and the central portion of the back of the cathode plate are concave. The circular feed inlet 203-1 is in contact with the surface to feed the RF/VHF power signal to the cathode plate. A hole 204-1 is formed in the middle of the corresponding feed inlet 203-1 in the middle of the cathode plate shield 204 so that the power feeding component 201 does not come into contact with the cathode plate shield 204 when it is taken out from the cathode plate 203, and the other end of the power feeding component 201 passes. The hole 201-3 is connected to the power connector 205, and has a high temperature resistant ceramic insulating layer 202 at the waist to prevent contact with the cathode plate shield 204. The signal feeding component 201 is copper with good conductivity, and the front door plate 215 is the substrate 206. After being loaded into the deposition box 02, the upper hook 215-2 is hung on the mounting lug 216-1 on the side frame 216, and the lower side is inserted into the Z-shaped tab 216-2, so that a relatively closed inside the deposition box 02 is formed. Space. The deposition box 02 is pushed into the vacuum chamber 01 along the rail 104, so that the inlet on the gas pipe 220 fixed on the deposition box 02 and the gas system inlet 101 on the vacuum chamber 01 are docked into the nozzle inside the vacuum chamber 01, and closed. The vacuum chamber movable door 103 on the vacuum chamber 01 is evacuated to a desired state by a vacuum system, and then subjected to a vapor deposition process to complete vapor deposition coating.

Example 2:

 The electrode plate is vertical, the cathode plate feeding inlet is circular, the signal feeding component is flat at the waist, the feeding surface is semicircular, the cathode plate is insulated from the shielding cover, and the cathode plate shielding cover is provided with a through hole.

 Figure 7 uses the deposition cartridge as in Example 1. Eight substrates 206 can be coated simultaneously. The two cathode plates 203 share one anode plate 208, and two anode plates 208 and four cathode plates 203 constitute four pairs of electrodes, and eight substrates 206 can be simultaneously coated. Specific steps are as follows:

a) 8 glass substrates with a 600 nm thick transparent conductive film (1640 hidden X 707mmX 3 legs) Placed in the substrate in the deposition box 02 with the film facing outward and the glass facing the electrode plate.

 b) Opening the vacuum chamber movable door 103, pushing the deposition box 02 into the vacuum chamber 01 along the rail 104, and closing the vacuum chamber movable door 103 of the vacuum chamber 01.

c) Vacuum pumped to 5. 0 X l (T ⁴ Pa, argon gas is introduced, when the pressure in the chamber reaches 60Pa, open the 40.68MHz VHF power supply, clean the chamber with 400W power for 2 minutes, turn off the power .

 d) After pumping a high vacuum to 5. 0 X l (about TPa, wash twice with argon.

 e) According to 5slpm, enter the mixed gas (silane plus hydrogen). When the pressure in the chamber reaches 60Pa, turn on the 40.68MHz VHF power supply, discharge at 400W, and deposit the microcrystalline silicon intrinsic layer for 40 minutes.

 f) Turn off the power and draw a high vacuum.

 g) Fill with nitrogen to atmospheric pressure, open the vacuum chamber movable door 103, push out the deposition box 02, and cool the TC0 glass at room temperature.

 With this feeding form, a uniform electric field of a 40.68 MHz VHF power supply can be realized, and a microcrystalline silicon film having a film thickness unevenness of about 5% can be deposited on a TC0 glass of 1640 awake X 707 mm (length X width). , the crystallinity is adjustable.

Example 3:

 The electrode plate is vertical, the cathode plate feeding inlet is circular, the signal feeding component is flat at the waist, the feeding surface is semicircular, the cathode plate is insulated from the shielding cover, and the cathode plate shielding cover is provided with a through hole.

 Figure 8 uses the deposition box as in Example 1. 24 substrates 206 can be coated simultaneously. The two cathode plates 203 share one anode plate 208, and six anode plates 208 and twelve cathode plates 203 constitute twelve pairs of electrodes, and 24 substrates 206 can be simultaneously coated. Specific steps are as follows:

 a) Four glass substrates 206 (1640 mm X 707 mm X 3 mm) with a 600 nm thick transparent conductive film were placed in the substrate position in the deposition cartridge 02 with the film facing outward and the glass facing the electrode plate.

b) opening the vacuum chamber movable door 103, pushing the deposition box 02 along the rail 104 into the vacuum chamber 01, closing The vacuum chamber movable door 103 of the vacuum chamber 01 is good.

c) After the vacuum is pumped to 5. 0 X 10— ⁴ Pa, argon gas is introduced. When the pressure in the chamber reaches 60 Pa, the 40.68 MHz VHF power supply is turned on, and the chamber is cleaned by 400 W power for 2 minutes to turn off the power.

After high pumping d) to a vacuum of about 5. 0 X 10- ⁴ Pa, washed twice with argon.

 e) According to 5slpm, enter the mixed gas (silicon germanium and hydrogen). When the gas pressure in the chamber reaches 60Pa, turn on the 40.68MHz VHF power supply, discharge at 400W, and deposit the microcrystalline silicon intrinsic layer for 40 minutes.

 f) Turn off the power and draw a high vacuum.

 g) Fill with nitrogen to atmospheric pressure, open the vacuum chamber movable door 103, push out the deposition box 02, and cool the TC0 glass at room temperature.

 8%左右的微晶硅。 With this type of feed, a uniform electric field of 40. 68MHz VHF power supply can be achieved, on the TC0 glass of 1640mm X 707mm (length X width) can deposit microcrystalline silicon with a film thickness unevenness of about 4.0% film.

 The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and particularly, the shape of the feed assembly and the cathode plate can be within the knowledge of those skilled in the art. Various changes are made without departing from the spirit of the invention.

Claims

A deposition box for a silicon-based thin film solar cell, comprising an electrode plate assembly, a signal feed assembly, and a vacuum chamber, further comprising a cathode plate shield, wherein the chamber is a movable chamber with a roller a chamber in which an electrode array composed of electrode plates is mounted, the feed inlet being located in a concave circular or semi-circular surface in a central region of the back surface of the cathode plate of the electrode plate assembly, in a circular or semi-circular feed inlet thereof The signal feeding component of the inner surface contact connection is connected to the negative pole of the RF/VHF power supply signal.  The signal feeding component has a semicircular or circular end face;  The shielding plate of the cathode plate has a through hole.  Insulation between the cathode plate and the shield;  The electrode array has at least one set of cathode plates and one anode plate.  2. A deposition box for a silicon-based thin film solar cell according to claim 1, wherein said set of cathode plates and an anode plate are respectively oriented from the two faces of the anode plate toward the symmetrically placed cathode plates. Effective discharge of the working surface.  3. A deposition cassette for a silicon-based thin film solar cell according to claim 1, wherein said signal feed assembly comprises a copper feed core and an insulating layer and an outer shield.  4. A deposition box for a silicon-based thin film solar cell according to claim 1, wherein said cathode plate is a single-sided discharge, and the shield of the cathode plate comprises a ceramic insulating layer and a shielding layer, and the shielding cover covers the entire The back and sides of the cathode plate.  The deposition box of a silicon-based thin film solar cell according to any one of claims 1 to 4, wherein the electrode is composed of a plurality of cathode plates with a shield and a plurality of grounded anode plates. , an electrode array that constitutes a certain interval of discharge.  6. A deposition box for a silicon-based thin film solar cell according to claim 5, wherein said cathode plate shield further comprises a RF/VHF power signal fed to a center of the back of the cathode plate. And shielding around the sides. 7. A deposition cassette for a silicon-based thin film solar cell according to claim 5, wherein The signal feeding component is formed in a zigzag shape by a waist and a head, and has a ceramic insulating layer at the waist. The metal feeding core is an RF/VHF feeder to form an electric conductor.  8. A deposition box for a silicon-based thin film solar cell according to claim 1, characterized in that a cathode output port and a power source of the RF/VHF power supply signal are connected to the other end of the signal feeding component of the hand. Matcher.  9. A signal feeding method for a deposition box of a silicon-based thin film solar cell, wherein a signal feeding mode of the electrode plate assembly and the feeding assembly in the chamber is characterized in that the chamber with the movable roller is mounted by the electrode plate An electrode array composed of components, an electrode array of at least one set of cathode plates and an anode plate;  The feed inlet is located in a concave circular or semi-circular surface in the central region of the back surface of the cathode plate of the electrode plate, and is in contact with the feed-in assembly at its inner surface;  The signal feed mode is a face feed;  a semicircular or circular surface of the feed assembly contacts the circular or semi-circular surface feed inlet of the cathode plate; feeding RF/VHF power supply signals;  The cathode plate shield and the anode plate of the electrode plate are grounded.  10. A signal feeding method for a deposition box of a silicon-based thin film solar cell according to claim 9, wherein said electrode is fed by a plurality of sets of feeding components and electrode plate assemblies in a plane feeding manner. The high frequency power supply signal is fed to the electrode plate feed inlet to form an electrode array having a certain discharge pitch.  11. A signal feeding method for a deposition box of a silicon-based thin film solar cell according to claim 9, wherein said zigzag feeding member has a ceramic insulating layer at the waist, and the metal feeding core is RF/very The high frequency feed line constitutes an electrical conductor.  12 . The signal feeding method of a deposition box of a silicon-based thin film solar cell according to claim 11 , wherein the other end of the electrical conductor of the feeding component is connected to a cathode of an RF/VHF power supply signal. Output port and power supply matcher.